Pesticides based on cyclic polysiloxanes

ABSTRACT

The present invention relates to immediately acting pest control compositions based on cyclic polysiloxanes, which can be employed without a residue and without a lasting action.

The present invention relates to immediately acting pest controlcompositions based on cyclic polysiloxanes which can be employed withouta residue and without a lasting action.

It was known that cyclic polysiloxanes having 4 and 5 siloxane units areinsecticidally active. It was also known that insects can be killed byspraying using polysiloxanes (U.S. Pat. No. 4 654 328).

Use in practice shows, however, that problems occur during use. Cyclicpolysiloxanes having 4 siloxane units crystallize out at temperaturesbelow about 18° C. and can then no longer be sprayed without problems.No satisfactory action results from spraying insects with cyclicpolysiloxanes from aerosol sprays which produce an average droplet sizeof 50μ.

The invention therefore relates to the following mixtures andcompositions:

1. Immediately acting insecticidal and acaricidal composition which canbe used without a residue and without a lasting action and is based oncyclic polysiloxanes of the formula (I)

in which

R represents identical or different radicals from the group consistingof methyl, ethyl and propyl,

n represents integers from 3 to 6,

which are sprayed onto the pests in the customary manner with an averagedroplet size in the spray mist of 130 to 500μ (diameter).

2. Composition according to point 1 (above), characterized in that itpredominantly comprises, as the constituent of the formula (I),compounds in which the index n is 5.

3. Mixture of cyclic polysiloxanes of the formula (I)

in which

R represents identical or different radicals from the group consistingof methyl, ethyl and propyl,

n represents integers from 3 to 6,

characterized in that the constituents of the formula (I) with theindices 4 and 5 is present in the weight ratio

n=4<85% (weight)

n=5>15% (weight).

4. Mixture according to point 3 (above), characterized in that theconstituents of the formula (I) with the indices 4 and 5 are present inthe weight ratio

n=4 85 to 50% by weight

n=5 15 to 50% by weight.

5. Mixture according to point 3 (above), characterized in that theconstituents of the formula (I) with the indices 4 and 5 are present inthe weight ratio

n=4 80 to 60% by weight

n=5 20 to 40% by weight.

6. Mixture according to point 3 (above), characterized in that theconstituents of the formula (I) with the indices 4 and 5 are present inthe weight ratio

n=4 75% by weight

n=5 25% by weight.

The compositions according to the invention have considerable advantagesfor practical use. Their action on pests starts immediately, i.e. theuser sees the success of the control measure directly. The activecompound acts exclusively in direct contact with the pest, andpreventive treatment (residual action) is not possible. The compositionsare used only during an acute attack and only directly on the pests tobe controlled. That is to say, no preventive and superfluous amounts ofactive compound are spread into the environment.

Beneficial organisms can be protected by the controlled use. The activecompound is non-toxic to plants, mammals and humans.

The active compound evaporates rapidly from surfaces affected (plants,furniture, walls, window panes), without leaving behind residues.

The active compound is degraded abiotically within a short time by theaction of light.

The compositions according to the invention are suitable for controllinganimal pests, preferably arthropods, in particular insects andarachnids, which are encountered in agriculture, in forestry, in theprotection of stored products and of materials, and in the field ofhygiene. They are active against normally sensitive and resistantspecies and against all or some stages of development.

The abovementioned pests include:

From the order of the Isopoda, for example, Oniscus asellus,Armadillidium vulgare and Porcellio scaber.

From the order of the Diplopoda, for example, Blaniulus guttulatus.

From the order of the Chilopoda, for example, Geophilus carpophagus andScutigera spec.

From the order of the Symphyla, for example, Scutigerella immaculata.

From the order of the Thysanura, for example, Lepisma saccharina.

From the order of the Collembola, for example, Onychiurus armatus.

From the order of the Orthoptera, for example, Blatta orientalis,Periplaneta americana, Leucophaea maderae, Blattella germanica, Achetadomesticus, Gryllotalpa spp., Locusta migratoria migratorioides,Melanoplus differentialis and Schistocerca gregaria.

From the order of the Dermaptera, for example, Forficula auricularia.

From the order of the Isoptera, for example, Reticulitermes spp.

From the order of the Anoplura, for example, Pediculus humanus corporis,Haematopinus spp. and Linognathus spp.

From the order of the Mallophaga, for example, Trichodectes spp. andDamalinea spp.

From the order of the Thysanoptera, for example, Hercinothrips femoralisand Thrips tabaci.

From the order of the Heteroptera, for example, Eurygaster spp.,Dysdercus intermedius, Piesma quadrata, Cimex lectularius, Rhodniusprolixus and Triatoma spp.

From the order of the Homoptera, for example, Aleurodes brassicae,Bemisia tabaci, Trialeurodes vaporariorum, Aphis gossypii, Brevicorynebrassicae, Cryptomyzus ribis, Aphis fabae, Aphis pomi, Eriosomalanigerum, Hyalopterus arundinis, Phylloxera vastatrix, Pemphigus spp.,Macrosiphum avenae, Myzus spp., Phorodon humuli, Rhopalosiphum padi,Empoasca spp., Euscelis bilobatus, Nephotettix cincticeps, Lecaniumcorni, Saissetia oleae, Laodelphax striatellus, Nilaparvata lugens,Aonidiella aurantii, Aspidiotus hederae, Pseudococcus spp. and Psyllaspp.

From the order of the Lepidoptera, for example, Pectinophoragossypiella, Bupalus piniarius, Cheimatobia brumata, Lithocolletisblancardella, Hyponomeuta padella, Plutella maculipennis, Malacosomaneustria, Euproctis chrysorrhoea, Lymantria spp., Bucculatrixthurberiella, Phyllocnistis citrella, Agrotis spp., Euxoa spp., Feltiaspp., Earias insulana, Heliothis spp., Laphygma exigua, Mamestrabrassicae, Panolis flammea, Prodenia litura, Spodoptera spp.,Trichoplusia ni, Carpocapsa pomonella, Pieris spp., Chilo spp., Pyraustanubilalis, Ephestia kuehniella, Galleria mellonella, Tineolabisselliella, Tinea pellionella, Hofinannophila pseudospretella,Cacoecia podana, Capua reticulana, Choristoneura fumiferana, Clysiaambiguella, Homona magnanima and Tortrix viridana.

From the order of the Coleoptera, for example, Anobium punctatum,Rhizopertha dominica, Bruchidius obtectus, Acanthoscelides obtectus,Hylotrupes bajulus, Agelastica alni, Leptinotarsa decemlineata, Phaedoncochleariae, Diabrotica spp., Psylliodes chrysocephala, Epilachnavarivestis, Atomaria spp., Oryzaephilus surinamensis, Anthonomus spp.,Sitophilus spp., Otiorrhynchus sulcatus, Cosmopolites sordidus,Ceuthorrhynchus assimilis, Hypera postica, Dermestes spp., Trogodermaspp., Anthrenus spp., Attagenus spp., Lyctus spp., Meligethes aeneus,Ptinus spp., Niptus hololeucus, Gibbium psylloides, Tribolium spp.,Tenebrio molitor, Agriotes spp., Conoderus spp., Melolontha melolontha,Amphimallon solstitialis and Costelytra zealandica.

From the order of the Hymenoptera, for example, Diprion spp., Hoplocampaspp., Lasius spp., Monomorium pharaonis and Vespa spp.

From the order of the Diptera, for example, Aedes spp., Anopheles spp.,Culex spp., Drosophila melanogaster, Musca spp., Fannia spp., Calliphoraerythrocephala, Lucilia spp., Chrysomyia spp., Cuterebra spp.,Gastrophilus spp., Hyppobosca spp., Stomoxys spp., Oestrus spp.,Hypodermna spp., Tabanus spp., Tannia spp., Bibio hortulanus, Oscinellafrit, Phorbia spp., Pegomyia hyoscyami, Ceratitis capitata, Dacus oleaeand Tipula paludosa.

From the order of the Siphonaptera, for example, Xenopsylla cheopis andCeratophyllus spp.

From the order of the Arachnida, for example, Scorpio maurus andLatrodectus mactans.

From the order of the Acarina, for example, Acarus siro, Argas spp.,Ornithodoros spp., Dermanyssus gallinae, Eriophyes ribis, Phyllocoptrutaoleivora, Boophilus spp., Rhipicephalus spp., Amblyomma spp., Hyalommaspp., Ixodes spp., Psoroptes spp., Chorioptes spp., Sarcoptes spp.,Tarsonemus spp., Bryobia praetiosa, Panonychus spp. and Tetranychus spp.

The compositions are suitable for controlling animal pests, such asarthropods, preferably insects and arachnids, encountered in animalhusbandry and animal breeding of stock, breeding, zoo, laboratory andtest animals and pets, and have favorable toxicity to warm-bloodedanimals. They are active here against all or some stages of developmentof the pests and against resistant and normally sensitive species of thepests.

The pests include:

From the order of the Anoplura, for example, Haematopinus spp.,Linognathus spp., Solenopotes spp., Pediculus spp. and Pthirus spp.;

From the order of the Mallophaga, for example, Trimenopon spp., Menoponspp., Eomenacanthus spp., Menacanthus spp., Trichodectes spp., Felicolaspp., Damalinea spp. and Bobiola spp.;

From the order of the Diptera, for example, Chrysops spp., Tabanus spp.,Musca spp., Hydrotaea spp., Muscina spp., Haematobosca spp., Haematobiaspp., Stomoxys spp., Fannia spp., Glossina spp., Lucilia spp.,Calliphora spp., Auchmeromyia spp., Cardylobia spp., Cochiomyia spp.,Chrysomyia spp., Sarcophaga spp., Wohlfartia spp., Gaserophilus spp.,Oesteromyia spp., Oedemagena sp., Hypoderma spp., Oestrus spp.,Rhinoestrus spp., Melophagus spp. and Hippobosca spp.

From the order of the Siphonaptera, for example, Ctenocephalides spp.,Echidnophaga spp. and Ceratophyllus spp.

From the order of the Metastigmata, for example, Hyalomma spp.,Rhipicephalus spp., Boophilus spp., Ambyomma spp., Haemophysalis spp.,Dermacentor spp., Ixodes spp., Argas spp., Ornithodorus spp. and Otobiusspp.; from the order of the Mesastigmata, for example, Dermanyssus spp.,Ornithonyssus spp. and Pneumonyssus spp.

From the order of the Prostigmata, for example, Cheyletiella spp.,Psorergates spp., Myobia spp., Demdex spp. and Neotrombicula spp.;

The domestic and stock animals include mammals, such as, for example,cattle, sheep, goats, horses, pigs, dogs, cats, camels, water buffalo,donkeys, rabbits, fallow deer and reindeer, fur-bearing animals, suchas, for example, mink, chinchilla and racoons, and birds, such as, forexample, chickens, turkeys, pheasants, geese and ducks.

The laboratory and test animals include, for example, mice, rats,guineapigs, golden hamsters, dogs and cats.

The pets include, for example, dogs and cats.

The compositions according to the invention can particularly preferablybe employed in closed rooms, such as flats, halls or the like. They areparticularly suitable for controlling animal pests and nuisances whichoccur in the home.

In this context, there may be mentioned in particular flies, mosquitoes,wasps, ants, cockroaches and silverfish.

Formula (I) provides a general definition of the cyclic polysiloxanes.

Compounds of the formula (I) in which R represents methyl and nrepresents 4 and 5 are particularly preferred.

The cyclic polysiloxanes octamethylcyclotetrasiloxane anddecamethylcyclopentasiloxane and their mixtures with one another andwith cyclic polysiloxanes which are contained in them due to thepreparation process may be mentioned in particular.

As already mentioned, the compositions according to the invention aresprayed directly on the pests or nuisances to be controlled. This iseffected in the customary manner with pump sprays, aerosol sprays andspraying and atomizing apparatuses.

A prerequisite for successful treatment is an average droplet size ofthe active compound mist of 130 to 500μ (diameter). The distribution ofthe droplet size is between 100 and 700μ, and 90% of all drops here aresmaller than 600μ. The spraying and atomizing apparatuses must beconstructed such that they guarantee this droplet size.

Only this droplet size guarantees that the pests are affected by anadequate amount of active compound with normal handling (spraying from adistance of about 20 to 100 cm). For example, it has been found thatspraying with the active compounds of average droplet size <80μ at adistance of 60 cm had no action at all on flies.

A distribution of the droplet sizes from 150 to 500μ, where 90% of alldrops are <420μ, is preferred. This corresponds to a mean droplet sizeof 160 to 300μ.

Decamethylcyclopentasiloxane is particularly suitable as the activecompound and agent. This active compound is stable at low temperatures,without crystallizing out, and is therefore easy to store and use.

It is employed, in particular, if stability to low temperatures isimportant and rapid residue-free evaporation of the active compoundplays a minor role.

Mixtures of octamethylcyclotetrasiloxane anddecamethylcyclopentasiloxane are particularly preferred if the contentof the pentasiloxane is >15% (weight). Such mixtures have the advantageof a good stability toward crystallizing out at low temperatures,associated with rapid residue-free evaporation of the mixture from thesurfaces affected. This makes such mixtures particularly suitable foruse in the home.

The cyclic polysiloxanes are particularly preferably used as such,without further additions, such as solvents, in the compositionsaccording to the invention.

However, it is easily possible to add the customary additives, such assolvents, surfactants and perfume oils, to the compositions.

EXAMPLE A Test with Flies (Musca domestica)—Spry Method

Test animals: adult Musca domestica, Reichswald strain (multiresistant)

Solvent: not applicable

To produce a suitable formulation, 25 parts ofdecamethylcyclopentasiloxane are mixed with 75 parts ofoctamethylcyclotetrasiloxane.

100 ml of this active compound preparation are transferred to spraybottles with nozzle diameter. Wire gauze disks of 10.8 cm diameter areintroduced (curved hemispherically toward the base) into PP containers(Ø9.7 cm, H 8 cm). 20 flies are stunned with CO₂ and transferred to thegauze. The container is closed with a second wire gauze disk, in thiscase curved upward, and kept at room temperature for 30 minutes untilall the flies show normal activity again. The container is heldhorizontally at a distance of 15 cm from the spray head of the spraybottle. By operating the spray lever 3 times, a total of 3 ml of activecompound preparation are sprayed onto the flies. The vessel is thenplaced with the opening at the top again.

After 1 minute, 100% of the flies were dead.

EXAMPLE B Musca domestica/Stomoxys calcitrans

(Experimental Treatment Under Conditions in Practice in a Pigsty)

The test was carried out in a pigsty. 3 pens in which there were a totalof 6 animals were occupied in the sty. The fly infestation was 50-100flies per animal.

Method

The formulation described in Example A was applied undiluted under apressure of 4.5 mbar. (Nozzle: Holder series nozzle “Merkur” of brasswith a swirl body, nozzle bore 1.5 mm: spray angle about 65°). The spraypressure was regulated via a breathing air bottle.

Only the regions of the sty where there were larger accumulations offlies were sprayed (M. domestica and S. calcitrans). The amount appliedwas 30 to 50 g of formulation per m².

Flies which were affected and wetted by the spray mist fell to the flooror remained suspended on the wall or the animals directly after thetreatment. No recovery was observed. M. domestica and S. calcitrans wereaffected by the spray composition in the same manner.

EXAMPLE C

The formulation described in Example A was applied undiluted withvarious spray and misting apparatuses (see Table 1) in 2 stables whereflies (M. domestica) had previously been released (5 000 to 10 000 perroom).

TABLE 1 Application Musca domestica Spray apparatus according + + toExample B, 4-5 bar, fine nozzle ULV (ROFA) − Cold mist (Microjet) − + += good action − = no action

The Rofa apparatus is used for ULV application and is distinguished by adistribution of the particular formulation in very fine droplets (5 to30μ). The fine droplets are not sufficient to achieve an adequateaction, even if the animals are sprayed over a relatively long period oftime.

The same applies to the cold mist apparatus “Mikrojet”, whichdistributes the substance with an average droplet size of <80μ.

Tests with the apparatus described in Example B again led to the resultdescribed. Flies which were affected directly by the droplets diedwithin 15 minutes.

The spray coating was no longer detectable on the walls (lime sandstone)after about 15 minutes,

EXAMPLE D

A plant heavily infested with aphids was sprayed using the pressurizedspray apparatus. The aphids affected by the spray mist could be shakenoff from the plant within 5 minutes after the treatment and did notrecover.

What is claimed is:
 1. A method for controlling insects and arachnidscomprising the step of spraying a composition comprising at least onecyclic polysiloxane of the formula (I)

wherein R represents identical or different radicals selected from thegroup consisting of methyl, ethyl and propyl, and n represents integersfrom 3 to 6, onto the pests, wherein the droplets in the spray mist havean average diameter of from about 130 to about 500μ.
 2. The method ofclaim 1 wherein the composition comprises a mixture of cyclicpolysiloxanes of the formula (I)

wherein R represents identical or different radicals selected from thegroup consisting of methyl, ethyl and propyl, n represents integers from3 to 6, wherein the constituents of the formula (I) with the indices 4and 5 are present in the weight ratio n=4, <85% by weight, and n=5, >15%by weight.
 3. The method of claim 2 wherein the constituents of theformula (I) with the indices 4 and 5 are present in the weight ration=4, 50 to 85% by weight, and n=5, 15 to 50% by weight.
 4. The method ofclaim 2 wherein the constituents of the formula (I) with the indices 4and 5 are present in the weight ratio n=4, 60 to 80% by weight, and n=5,20 to 40% by weight.
 5. The method of claim 2 wherein the constituentsof the formula (I) with the indices 4 and 5 are present in the weightratio n=4, 75% by weight and n=5, 25% by weight.
 6. The method of claim1 wherein the composition comprises predominantly cyclic polysiloxanesin which n=5.